There will be some flight restrictions for UAV and Model Aircraft between 14 July 2012 - 15 August 2012. This mainly effects the London region so its best to avoid these areas if you plan on flying there.
Ardupilot Mega 2560
As the Ardupilot Mega software improves each day it requires more and more memory, and fo rthis reason the memory of the current APM1280 board are running very low. For this reason the newer APM2560 boards where released which have twice as much memory.
It is not mandatory to upgrade to the latest board, but it is recommended to continue ot use all of the new features to come in the future.. The final stable release for APM1280 boards will be released soon(V2.3) which works great and has many features. After this point you will need to upgrade to the newer board that has additional memory for all the latest and greatest features.